content: /**
   * Copyright (c) 2016-present, RxJava Contributors.
   *
   * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in
   * compliance with the License. You may obtain a copy of the License at
   *
   * http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software distributed under the License is
   * distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See
   * the License for the specific language governing permissions and limitations under the License.
   */
  
  package io.reactivex.observable.internal.operators;
  
  import static org.junit.Assert.*;
  import static org.mockito.ArgumentMatchers.*;
  import static org.mockito.Mockito.*;
  
  import java.util.*;
  import java.util.concurrent.*;
  import java.util.concurrent.atomic.AtomicReference;
  
  import org.junit.*;
  import org.mockito.InOrder;
  
  import io.reactivex.common.*;
  import io.reactivex.common.exceptions.TestException;
  import io.reactivex.common.functions.*;
  import io.reactivex.common.internal.functions.Functions;
  import io.reactivex.observable.*;
  import io.reactivex.observable.Observable;
  import io.reactivex.observable.Observer;
  import io.reactivex.observable.observers.*;
  import io.reactivex.observable.subjects.PublishSubject;
  
  public class ObservableDelayTest {
      private Observer<Long> observer;
      private Observer<Long> observer2;
  
      private TestScheduler scheduler;
  
      @Before
      public void before() {
          observer = TestHelper.mockObserver();
          observer2 = TestHelper.mockObserver();
  
          scheduler = new TestScheduler();
      }
  
      @Test
      public void testDelay() {
          Observable<Long> source = Observable.interval(1L, TimeUnit.SECONDS, scheduler).take(3);
          Observable<Long> delayed = source.delay(500L, TimeUnit.MILLISECONDS, scheduler);
          delayed.subscribe(observer);
  
          InOrder inOrder = inOrder(observer);
          scheduler.advanceTimeTo(1499L, TimeUnit.MILLISECONDS);
          verify(observer, never()).onNext(anyLong());
          verify(observer, never()).onComplete();
          verify(observer, never()).onError(any(Throwable.class));
  
          scheduler.advanceTimeTo(1500L, TimeUnit.MILLISECONDS);
          inOrder.verify(observer, times(1)).onNext(0L);
          inOrder.verify(observer, never()).onNext(anyLong());
          verify(observer, never()).onComplete();
          verify(observer, never()).onError(any(Throwable.class));
  
          scheduler.advanceTimeTo(2400L, TimeUnit.MILLISECONDS);
          inOrder.verify(observer, never()).onNext(anyLong());
          verify(observer, never()).onComplete();
          verify(observer, never()).onError(any(Throwable.class));
  
          scheduler.advanceTimeTo(2500L, TimeUnit.MILLISECONDS);
          inOrder.verify(observer, times(1)).onNext(1L);
          inOrder.verify(observer, never()).onNext(anyLong());
          verify(observer, never()).onComplete();
          verify(observer, never()).onError(any(Throwable.class));
  
          scheduler.advanceTimeTo(3400L, TimeUnit.MILLISECONDS);
          inOrder.verify(observer, never()).onNext(anyLong());
          verify(observer, never()).onComplete();
          verify(observer, never()).onError(any(Throwable.class));
  
          scheduler.advanceTimeTo(3500L, TimeUnit.MILLISECONDS);
          inOrder.verify(observer, times(1)).onNext(2L);
          verify(observer, times(1)).onComplete();
          verify(observer, never()).onError(any(Throwable.class));
      }
  
      @Test
      public void testLongDelay() {
          Observable<Long> source = Observable.interval(1L, TimeUnit.SECONDS, scheduler).take(3);
          Observable<Long> delayed = source.delay(5L, TimeUnit.SECONDS, scheduler);
          delayed.subscribe(observer);
  
          InOrder inOrder = inOrder(observer);
  
          scheduler.advanceTimeTo(5999L, TimeUnit.MILLISECONDS);
          verify(observer, never()).onNext(anyLong());
          verify(observer, never()).onComplete();
          verify(observer, never()).onError(any(Throwable.class));
  
          scheduler.advanceTimeTo(6000L, TimeUnit.MILLISECONDS);
          inOrder.verify(observer, times(1)).onNext(0L);
          scheduler.advanceTimeTo(6999L, TimeUnit.MILLISECONDS);
          inOrder.verify(observer, never()).onNext(anyLong());
          scheduler.advanceTimeTo(7000L, TimeUnit.MILLISECONDS);
          inOrder.verify(observer, times(1)).onNext(1L);
          scheduler.advanceTimeTo(7999L, TimeUnit.MILLISECONDS);
          inOrder.verify(observer, never()).onNext(anyLong());
          scheduler.advanceTimeTo(8000L, TimeUnit.MILLISECONDS);
          inOrder.verify(observer, times(1)).onNext(2L);
          inOrder.verify(observer, times(1)).onComplete();
          inOrder.verify(observer, never()).onNext(anyLong());
          inOrder.verify(observer, never()).onComplete();
          verify(observer, never()).onError(any(Throwable.class));
      }
  
      @Test
      public void testDelayWithError() {
          Observable<Long> source = Observable.interval(1L, TimeUnit.SECONDS, scheduler)
          .map(new Function<Long, Long>() {
              @Override
              public Long apply(Long value) {
                  if (value == 1L) {
                      throw new RuntimeException("error!");
                  }
                  return value;
              }
          });
          Observable<Long> delayed = source.delay(1L, TimeUnit.SECONDS, scheduler);
          delayed.subscribe(observer);
  
          InOrder inOrder = inOrder(observer);
  
          scheduler.advanceTimeTo(1999L, TimeUnit.MILLISECONDS);
          verify(observer, never()).onNext(anyLong());
          verify(observer, never()).onComplete();
          verify(observer, never()).onError(any(Throwable.class));
  
          scheduler.advanceTimeTo(2000L, TimeUnit.MILLISECONDS);
          inOrder.verify(observer, times(1)).onError(any(Throwable.class));
          inOrder.verify(observer, never()).onNext(anyLong());
          verify(observer, never()).onComplete();
  
          scheduler.advanceTimeTo(5000L, TimeUnit.MILLISECONDS);
          inOrder.verify(observer, never()).onNext(anyLong());
          inOrder.verify(observer, never()).onError(any(Throwable.class));
          verify(observer, never()).onComplete();
      }
  
      @Test
      public void testDelayWithMultipleSubscriptions() {
          Observable<Long> source = Observable.interval(1L, TimeUnit.SECONDS, scheduler).take(3);
          Observable<Long> delayed = source.delay(500L, TimeUnit.MILLISECONDS, scheduler);
          delayed.subscribe(observer);
          delayed.subscribe(observer2);
  
          InOrder inOrder = inOrder(observer);
          InOrder inOrder2 = inOrder(observer2);
  
          scheduler.advanceTimeTo(1499L, TimeUnit.MILLISECONDS);
          verify(observer, never()).onNext(anyLong());
          verify(observer2, never()).onNext(anyLong());
  
          scheduler.advanceTimeTo(1500L, TimeUnit.MILLISECONDS);
          inOrder.verify(observer, times(1)).onNext(0L);
          inOrder2.verify(observer2, times(1)).onNext(0L);
  
          scheduler.advanceTimeTo(2499L, TimeUnit.MILLISECONDS);
          inOrder.verify(observer, never()).onNext(anyLong());
          inOrder2.verify(observer2, never()).onNext(anyLong());
  
          scheduler.advanceTimeTo(2500L, TimeUnit.MILLISECONDS);
          inOrder.verify(observer, times(1)).onNext(1L);
          inOrder2.verify(observer2, times(1)).onNext(1L);
  
          verify(observer, never()).onComplete();
          verify(observer2, never()).onComplete();
  
          scheduler.advanceTimeTo(3500L, TimeUnit.MILLISECONDS);
          inOrder.verify(observer, times(1)).onNext(2L);
          inOrder2.verify(observer2, times(1)).onNext(2L);
          inOrder.verify(observer, never()).onNext(anyLong());
          inOrder2.verify(observer2, never()).onNext(anyLong());
          inOrder.verify(observer, times(1)).onComplete();
          inOrder2.verify(observer2, times(1)).onComplete();
  
          verify(observer, never()).onError(any(Throwable.class));
          verify(observer2, never()).onError(any(Throwable.class));
      }
  
      @Test
      public void testDelaySubscription() {
          Observable<Integer> result = Observable.just(1, 2, 3).delaySubscription(100, TimeUnit.MILLISECONDS, scheduler);
  
          Observer<Object> o = TestHelper.mockObserver();
          InOrder inOrder = inOrder(o);
  
          result.subscribe(o);
  
          inOrder.verify(o, never()).onNext(any());
          inOrder.verify(o, never()).onComplete();
  
          scheduler.advanceTimeBy(100, TimeUnit.MILLISECONDS);
  
          inOrder.verify(o, times(1)).onNext(1);
          inOrder.verify(o, times(1)).onNext(2);
          inOrder.verify(o, times(1)).onNext(3);
          inOrder.verify(o, times(1)).onComplete();
  
          verify(o, never()).onError(any(Throwable.class));
      }
  
      @Test
      public void testDelaySubscriptionDisposeBeforeTime() {
          Observable<Integer> result = Observable.just(1, 2, 3).delaySubscription(100, TimeUnit.MILLISECONDS, scheduler);
  
          Observer<Object> o = TestHelper.mockObserver();
          TestObserver<Object> ts = new TestObserver<Object>(o);
  
          result.subscribe(ts);
          ts.dispose();
          scheduler.advanceTimeBy(100, TimeUnit.MILLISECONDS);
  
          verify(o, never()).onNext(any());
          verify(o, never()).onComplete();
          verify(o, never()).onError(any(Throwable.class));
      }
  
      @Test
      public void testDelayWithObservableNormal1() {
          PublishSubject<Integer> source = PublishSubject.create();
          final List<PublishSubject<Integer>> delays = new ArrayList<PublishSubject<Integer>>();
          final int n = 10;
          for (int i = 0; i < n; i++) {
              PublishSubject<Integer> delay = PublishSubject.create();
              delays.add(delay);
          }
  
          Function<Integer, Observable<Integer>> delayFunc = new Function<Integer, Observable<Integer>>() {
              @Override
              public Observable<Integer> apply(Integer t1) {
                  return delays.get(t1);
              }
          };
  
          Observer<Object> o = TestHelper.mockObserver();
          InOrder inOrder = inOrder(o);
  
          source.delay(delayFunc).subscribe(o);
  
          for (int i = 0; i < n; i++) {
              source.onNext(i);
              delays.get(i).onNext(i);
              inOrder.verify(o).onNext(i);
          }
          source.onComplete();
  
          inOrder.verify(o).onComplete();
          inOrder.verifyNoMoreInteractions();
  
          verify(o, never()).onError(any(Throwable.class));
      }
  
      @Test
      public void testDelayWithObservableSingleSend1() {
          PublishSubject<Integer> source = PublishSubject.create();
          final PublishSubject<Integer> delay = PublishSubject.create();
  
          Function<Integer, Observable<Integer>> delayFunc = new Function<Integer, Observable<Integer>>() {
  
              @Override
              public Observable<Integer> apply(Integer t1) {
                  return delay;
              }
          };
          Observer<Object> o = TestHelper.mockObserver();
          InOrder inOrder = inOrder(o);
  
          source.delay(delayFunc).subscribe(o);
  
          source.onNext(1);
          delay.onNext(1);
          delay.onNext(2);
  
          inOrder.verify(o).onNext(1);
          inOrder.verifyNoMoreInteractions();
          verify(o, never()).onError(any(Throwable.class));
      }
  
      @Test
      public void testDelayWithObservableSourceThrows() {
          PublishSubject<Integer> source = PublishSubject.create();
          final PublishSubject<Integer> delay = PublishSubject.create();
  
          Function<Integer, Observable<Integer>> delayFunc = new Function<Integer, Observable<Integer>>() {
  
              @Override
              public Observable<Integer> apply(Integer t1) {
                  return delay;
              }
          };
          Observer<Object> o = TestHelper.mockObserver();
          InOrder inOrder = inOrder(o);
  
          source.delay(delayFunc).subscribe(o);
          source.onNext(1);
          source.onError(new TestException());
          delay.onNext(1);
  
          inOrder.verify(o).onError(any(TestException.class));
          inOrder.verifyNoMoreInteractions();
          verify(o, never()).onNext(any());
          verify(o, never()).onComplete();
      }
  
      @Test
      public void testDelayWithObservableDelayFunctionThrows() {
          PublishSubject<Integer> source = PublishSubject.create();
  
          Function<Integer, Observable<Integer>> delayFunc = new Function<Integer, Observable<Integer>>() {
  
              @Override
              public Observable<Integer> apply(Integer t1) {
                  throw new TestException();
              }
          };
          Observer<Object> o = TestHelper.mockObserver();
          InOrder inOrder = inOrder(o);
  
          source.delay(delayFunc).subscribe(o);
          source.onNext(1);
  
          inOrder.verify(o).onError(any(TestException.class));
          inOrder.verifyNoMoreInteractions();
          verify(o, never()).onNext(any());
          verify(o, never()).onComplete();
      }
  
      @Test
      public void testDelayWithObservableDelayThrows() {
          PublishSubject<Integer> source = PublishSubject.create();
          final PublishSubject<Integer> delay = PublishSubject.create();
  
          Function<Integer, Observable<Integer>> delayFunc = new Function<Integer, Observable<Integer>>() {
  
              @Override
              public Observable<Integer> apply(Integer t1) {
                  return delay;
              }
          };
          Observer<Object> o = TestHelper.mockObserver();
          InOrder inOrder = inOrder(o);
  
          source.delay(delayFunc).subscribe(o);
          source.onNext(1);
          delay.onError(new TestException());
  
          inOrder.verify(o).onError(any(TestException.class));
          inOrder.verifyNoMoreInteractions();
          verify(o, never()).onNext(any());
          verify(o, never()).onComplete();
      }
  
      @Test
      public void testDelayWithObservableSubscriptionNormal() {
          PublishSubject<Integer> source = PublishSubject.create();
          final PublishSubject<Integer> delay = PublishSubject.create();
          Callable<Observable<Integer>> subFunc = new Callable<Observable<Integer>>() {
              @Override
              public Observable<Integer> call() {
                  return delay;
              }
          };
          Function<Integer, Observable<Integer>> delayFunc = new Function<Integer, Observable<Integer>>() {
  
              @Override
              public Observable<Integer> apply(Integer t1) {
                  return delay;
              }
          };
  
          Observer<Object> o = TestHelper.mockObserver();
          InOrder inOrder = inOrder(o);
  
          source.delay(Observable.defer(subFunc), delayFunc).subscribe(o);
  
          source.onNext(1);
          delay.onNext(1);
  
          source.onNext(2);
          delay.onNext(2);
  
          inOrder.verify(o).onNext(2);
          inOrder.verifyNoMoreInteractions();
          verify(o, never()).onError(any(Throwable.class));
          verify(o, never()).onComplete();
      }
  
      @Test
      public void testDelayWithObservableSubscriptionFunctionThrows() {
          PublishSubject<Integer> source = PublishSubject.create();
          final PublishSubject<Integer> delay = PublishSubject.create();
          Callable<Observable<Integer>> subFunc = new Callable<Observable<Integer>>() {
              @Override
              public Observable<Integer> call() {
                  throw new TestException();
              }
          };
          Function<Integer, Observable<Integer>> delayFunc = new Function<Integer, Observable<Integer>>() {
  
              @Override
              public Observable<Integer> apply(Integer t1) {
                  return delay;
              }
          };
  
          Observer<Object> o = TestHelper.mockObserver();
          InOrder inOrder = inOrder(o);
  
          source.delay(Observable.defer(subFunc), delayFunc).subscribe(o);
  
          source.onNext(1);
          delay.onNext(1);
  
          source.onNext(2);
  
          inOrder.verify(o).onError(any(TestException.class));
          inOrder.verifyNoMoreInteractions();
          verify(o, never()).onNext(any());
          verify(o, never()).onComplete();
      }
  
      @Test
      public void testDelayWithObservableSubscriptionThrows() {
          PublishSubject<Integer> source = PublishSubject.create();
          final PublishSubject<Integer> delay = PublishSubject.create();
          Callable<Observable<Integer>> subFunc = new Callable<Observable<Integer>>() {
              @Override
              public Observable<Integer> call() {
                  return delay;
              }
          };
          Function<Integer, Observable<Integer>> delayFunc = new Function<Integer, Observable<Integer>>() {
  
              @Override
              public Observable<Integer> apply(Integer t1) {
                  return delay;
              }
          };
  
          Observer<Object> o = TestHelper.mockObserver();
          InOrder inOrder = inOrder(o);
  
          source.delay(Observable.defer(subFunc), delayFunc).subscribe(o);
  
          source.onNext(1);
          delay.onError(new TestException());
  
          source.onNext(2);
  
          inOrder.verify(o).onError(any(TestException.class));
          inOrder.verifyNoMoreInteractions();
          verify(o, never()).onNext(any());
          verify(o, never()).onComplete();
      }
  
      @Test
      public void testDelayWithObservableEmptyDelayer() {
          PublishSubject<Integer> source = PublishSubject.create();
  
          Function<Integer, Observable<Integer>> delayFunc = new Function<Integer, Observable<Integer>>() {
  
              @Override
              public Observable<Integer> apply(Integer t1) {
                  return Observable.empty();
              }
          };
          Observer<Object> o = TestHelper.mockObserver();
          InOrder inOrder = inOrder(o);
  
          source.delay(delayFunc).subscribe(o);
  
          source.onNext(1);
          source.onComplete();
  
          inOrder.verify(o).onNext(1);
          inOrder.verify(o).onComplete();
          inOrder.verifyNoMoreInteractions();
          verify(o, never()).onError(any(Throwable.class));
      }
  
      @Test
      public void testDelayWithObservableSubscriptionRunCompletion() {
          PublishSubject<Integer> source = PublishSubject.create();
          final PublishSubject<Integer> sdelay = PublishSubject.create();
          final PublishSubject<Integer> delay = PublishSubject.create();
          Callable<Observable<Integer>> subFunc = new Callable<Observable<Integer>>() {
              @Override
              public Observable<Integer> call() {
                  return sdelay;
              }
          };
          Function<Integer, Observable<Integer>> delayFunc = new Function<Integer, Observable<Integer>>() {
  
              @Override
              public Observable<Integer> apply(Integer t1) {
                  return delay;
              }
          };
  
          Observer<Object> o = TestHelper.mockObserver();
          InOrder inOrder = inOrder(o);
  
          source.delay(Observable.defer(subFunc), delayFunc).subscribe(o);
  
          source.onNext(1);
          sdelay.onComplete();
  
          source.onNext(2);
          delay.onNext(2);
  
          inOrder.verify(o).onNext(2);
          inOrder.verifyNoMoreInteractions();
          verify(o, never()).onError(any(Throwable.class));
          verify(o, never()).onComplete();
      }
  
      @Test
      public void testDelayWithObservableAsTimed() {
          Observable<Long> source = Observable.interval(1L, TimeUnit.SECONDS, scheduler).take(3);
  
          final Observable<Long> delayer = Observable.timer(500L, TimeUnit.MILLISECONDS, scheduler);
  
          Function<Long, Observable<Long>> delayFunc = new Function<Long, Observable<Long>>() {
              @Override
              public Observable<Long> apply(Long t1) {
                  return delayer;
              }
          };
  
          Observable<Long> delayed = source.delay(delayFunc);
          delayed.subscribe(observer);
  
          InOrder inOrder = inOrder(observer);
          scheduler.advanceTimeTo(1499L, TimeUnit.MILLISECONDS);
          verify(observer, never()).onNext(anyLong());
          verify(observer, never()).onComplete();
          verify(observer, never()).onError(any(Throwable.class));
  
          scheduler.advanceTimeTo(1500L, TimeUnit.MILLISECONDS);
          inOrder.verify(observer, times(1)).onNext(0L);
          inOrder.verify(observer, never()).onNext(anyLong());
          verify(observer, never()).onComplete();
          verify(observer, never()).onError(any(Throwable.class));
  
          scheduler.advanceTimeTo(2400L, TimeUnit.MILLISECONDS);
          inOrder.verify(observer, never()).onNext(anyLong());
          verify(observer, never()).onComplete();
          verify(observer, never()).onError(any(Throwable.class));
  
          scheduler.advanceTimeTo(2500L, TimeUnit.MILLISECONDS);
          inOrder.verify(observer, times(1)).onNext(1L);
          inOrder.verify(observer, never()).onNext(anyLong());
          verify(observer, never()).onComplete();
          verify(observer, never()).onError(any(Throwable.class));
  
          scheduler.advanceTimeTo(3400L, TimeUnit.MILLISECONDS);
          inOrder.verify(observer, never()).onNext(anyLong());
          verify(observer, never()).onComplete();
          verify(observer, never()).onError(any(Throwable.class));
  
          scheduler.advanceTimeTo(3500L, TimeUnit.MILLISECONDS);
          inOrder.verify(observer, times(1)).onNext(2L);
          verify(observer, times(1)).onComplete();
          verify(observer, never()).onError(any(Throwable.class));
      }
  
      @Test
      public void testDelayWithObservableReorder() {
          int n = 3;
  
          PublishSubject<Integer> source = PublishSubject.create();
          final List<PublishSubject<Integer>> subjects = new ArrayList<PublishSubject<Integer>>();
          for (int i = 0; i < n; i++) {
              subjects.add(PublishSubject.<Integer> create());
          }
  
          Observable<Integer> result = source.delay(new Function<Integer, Observable<Integer>>() {
  
              @Override
              public Observable<Integer> apply(Integer t1) {
                  return subjects.get(t1);
              }
          });
  
          Observer<Object> o = TestHelper.mockObserver();
          InOrder inOrder = inOrder(o);
  
          result.subscribe(o);
  
          for (int i = 0; i < n; i++) {
              source.onNext(i);
          }
          source.onComplete();
  
          inOrder.verify(o, never()).onNext(anyInt());
          inOrder.verify(o, never()).onComplete();
  
          for (int i = n - 1; i >= 0; i--) {
              subjects.get(i).onComplete();
              inOrder.verify(o).onNext(i);
          }
  
          inOrder.verify(o).onComplete();
  
          verify(o, never()).onError(any(Throwable.class));
      }
  
      @Test
      public void testDelayEmitsEverything() {
          Observable<Integer> source = Observable.range(1, 5);
          Observable<Integer> delayed = source.delay(500L, TimeUnit.MILLISECONDS, scheduler);
          delayed = delayed.doOnEach(new Consumer<Notification<Integer>>() {
  
              @Override
              public void accept(Notification<Integer> t1) {
                  System.out.println(t1);
              }
  
          });
          TestObserver<Integer> observer = new TestObserver<Integer>();
          delayed.subscribe(observer);
          // all will be delivered after 500ms since range does not delay between them
          scheduler.advanceTimeBy(500L, TimeUnit.MILLISECONDS);
          observer.assertValues(1, 2, 3, 4, 5);
      }
  
      @Test
      public void testBackpressureWithTimedDelay() {
          TestObserver<Integer> ts = new TestObserver<Integer>();
          Observable.range(1, Observable.bufferSize() * 2)
                  .delay(100, TimeUnit.MILLISECONDS)
                  .observeOn(Schedulers.computation())
                  .map(new Function<Integer, Integer>() {
  
                      int c;
  
                      @Override
                      public Integer apply(Integer t) {
                          if (c++ <= 0) {
                              try {
                                  Thread.sleep(500);
                              } catch (InterruptedException e) {
                              }
                          }
                          return t;
                      }
  
                  }).subscribe(ts);
  
          ts.awaitTerminalEvent();
          ts.assertNoErrors();
          assertEquals(Observable.bufferSize() * 2, ts.valueCount());
      }
  
      @Test
      public void testBackpressureWithSubscriptionTimedDelay() {
          TestObserver<Integer> ts = new TestObserver<Integer>();
          Observable.range(1, Observable.bufferSize() * 2)
                  .delaySubscription(100, TimeUnit.MILLISECONDS)
                  .delay(100, TimeUnit.MILLISECONDS)
                  .observeOn(Schedulers.computation())
                  .map(new Function<Integer, Integer>() {
  
                      int c;
  
                      @Override
                      public Integer apply(Integer t) {
                          if (c++ <= 0) {
                              try {
                                  Thread.sleep(500);
                              } catch (InterruptedException e) {
                              }
                          }
                          return t;
                      }
  
                  }).subscribe(ts);
  
          ts.awaitTerminalEvent();
          ts.assertNoErrors();
          assertEquals(Observable.bufferSize() * 2, ts.valueCount());
      }
  
      @Test
      public void testBackpressureWithSelectorDelay() {
          TestObserver<Integer> ts = new TestObserver<Integer>();
          Observable.range(1, Observable.bufferSize() * 2)
                  .delay(new Function<Integer, Observable<Long>>() {
  
                      @Override
                      public Observable<Long> apply(Integer i) {
                          return Observable.timer(100, TimeUnit.MILLISECONDS);
                      }
  
                  })
                  .observeOn(Schedulers.computation())
                  .map(new Function<Integer, Integer>() {
  
                      int c;
  
                      @Override
                      public Integer apply(Integer t) {
                          if (c++ <= 0) {
                              try {
                                  Thread.sleep(500);
                              } catch (InterruptedException e) {
                              }
                          }
                          return t;
                      }
  
                  }).subscribe(ts);
  
          ts.awaitTerminalEvent();
          ts.assertNoErrors();
          assertEquals(Observable.bufferSize() * 2, ts.valueCount());
      }
  
      @Test
      public void testBackpressureWithSelectorDelayAndSubscriptionDelay() {
          TestObserver<Integer> ts = new TestObserver<Integer>();
          Observable.range(1, Observable.bufferSize() * 2)
                  .delay(Observable.timer(500, TimeUnit.MILLISECONDS)
                  , new Function<Integer, Observable<Long>>() {
  
                      @Override
                      public Observable<Long> apply(Integer i) {
                          return Observable.timer(100, TimeUnit.MILLISECONDS);
                      }
  
                  })
                  .observeOn(Schedulers.computation())
                  .map(new Function<Integer, Integer>() {
  
                      int c;
  
                      @Override
                      public Integer apply(Integer t) {
                          if (c++ <= 0) {
                              try {
                                  Thread.sleep(500);
                              } catch (InterruptedException e) {
                              }
                          }
                          return t;
                      }
  
                  }).subscribe(ts);
  
          ts.awaitTerminalEvent();
          ts.assertNoErrors();
          assertEquals(Observable.bufferSize() * 2, ts.valueCount());
      }
  
      @Test
      public void testErrorRunsBeforeOnNext() {
          TestScheduler test = new TestScheduler();
  
          PublishSubject<Integer> ps = PublishSubject.create();
  
          TestObserver<Integer> ts = new TestObserver<Integer>();
  
          ps.delay(1, TimeUnit.SECONDS, test).subscribe(ts);
  
          ps.onNext(1);
  
          test.advanceTimeBy(500, TimeUnit.MILLISECONDS);
  
          ps.onError(new TestException());
  
          test.advanceTimeBy(1, TimeUnit.SECONDS);
  
          ts.assertNoValues();
          ts.assertError(TestException.class);
          ts.assertNotComplete();
      }
  
      @Test
      public void testDelaySupplierSimple() {
          final PublishSubject<Integer> ps = PublishSubject.create();
  
          Observable<Integer> source = Observable.range(1, 5);
  
          TestObserver<Integer> ts = new TestObserver<Integer>();
  
          source.delaySubscription(ps).subscribe(ts);
  
          ts.assertNoValues();
          ts.assertNoErrors();
          ts.assertNotComplete();
  
          ps.onNext(1);
  
          ts.assertValues(1, 2, 3, 4, 5);
          ts.assertComplete();
          ts.assertNoErrors();
      }
  
      @Test
      public void testDelaySupplierCompletes() {
          final PublishSubject<Integer> ps = PublishSubject.create();
  
          Observable<Integer> source = Observable.range(1, 5);
  
          TestObserver<Integer> ts = new TestObserver<Integer>();
  
          source.delaySubscription(ps).subscribe(ts);
  
          ts.assertNoValues();
          ts.assertNoErrors();
          ts.assertNotComplete();
  
          // FIXME should this complete the source instead of consuming it?
          ps.onComplete();
  
          ts.assertValues(1, 2, 3, 4, 5);
          ts.assertComplete();
          ts.assertNoErrors();
      }
  
      @Test
      public void testDelaySupplierErrors() {
          final PublishSubject<Integer> ps = PublishSubject.create();
  
          Observable<Integer> source = Observable.range(1, 5);
  
          TestObserver<Integer> ts = new TestObserver<Integer>();
  
          source.delaySubscription(ps).subscribe(ts);
  
          ts.assertNoValues();
          ts.assertNoErrors();
          ts.assertNotComplete();
  
          ps.onError(new TestException());
  
          ts.assertNoValues();
          ts.assertNotComplete();
          ts.assertError(TestException.class);
      }
  
      @Test
      public void delayWithTimeDelayError() throws Exception {
          Observable.just(1).concatWith(Observable.<Integer>error(new TestException()))
          .delay(100, TimeUnit.MILLISECONDS, true)
          .test()
          .awaitDone(5, TimeUnit.SECONDS)
          .assertFailure(TestException.class, 1);
      }
  
      @Test
      public void testOnErrorCalledOnScheduler() throws Exception {
          final CountDownLatch latch = new CountDownLatch(1);
          final AtomicReference<Thread> thread = new AtomicReference<Thread>();
  
          Observable.<String>error(new Exception())
                  .delay(0, TimeUnit.MILLISECONDS, Schedulers.newThread())
                  .doOnError(new Consumer<Throwable>() {
                      @Override
                      public void accept(Throwable throwable) throws Exception {
                          thread.set(Thread.currentThread());
                          latch.countDown();
                      }
                  })
                  .onErrorResumeNext(Observable.<String>empty())
                  .subscribe();
  
          latch.await();
  
          assertNotEquals(Thread.currentThread(), thread.get());
      }
  
      @Test
      public void dispose() {
          TestHelper.checkDisposed(PublishSubject.create().delay(1, TimeUnit.SECONDS));
  
          TestHelper.checkDisposed(PublishSubject.create().delay(Functions.justFunction(Observable.never())));
      }
  
      @Test
      public void doubleOnSubscribe() {
          TestHelper.checkDoubleOnSubscribeObservable(new Function<Observable<Object>, ObservableSource<Object>>() {
              @Override
              public ObservableSource<Object> apply(Observable<Object> o) throws Exception {
                  return o.delay(1, TimeUnit.SECONDS);
              }
          });
  
          TestHelper.checkDoubleOnSubscribeObservable(new Function<Observable<Object>, ObservableSource<Object>>() {
              @Override
              public ObservableSource<Object> apply(Observable<Object> o) throws Exception {
                  return o.delay(Functions.justFunction(Observable.never()));
              }
          });
      }
  
      @Test
      public void onCompleteFinal() {
          TestScheduler scheduler = new TestScheduler();
  
          Observable.empty()
          .delay(1, TimeUnit.MILLISECONDS, scheduler)
          .subscribe(new DisposableObserver<Object>() {
              @Override
              public void onNext(Object value) {
              }
  
              @Override
              public void onError(Throwable e) {
              }
  
              @Override
              public void onComplete() {
                  throw new TestException();
              }
          });
  
          try {
              scheduler.advanceTimeBy(1, TimeUnit.SECONDS);
              fail("Should have thrown");
          } catch (TestException ex) {
              // expected
          }
      }
  
      @Test
      public void onErrorFinal() {
          TestScheduler scheduler = new TestScheduler();
  
          Observable.error(new TestException())
          .delay(1, TimeUnit.MILLISECONDS, scheduler)
          .subscribe(new DisposableObserver<Object>() {
              @Override
              public void onNext(Object value) {
              }
  
              @Override
              public void onError(Throwable e) {
                  throw new TestException();
              }
  
              @Override
              public void onComplete() {
              }
          });
  
          try {
              scheduler.advanceTimeBy(1, TimeUnit.SECONDS);
              fail("Should have thrown");
          } catch (TestException ex) {
              // expected
          }
      }
  
      @Test
      public void itemDelayReturnsNull() {
          Observable.just(1).delay(new Function<Integer, Observable<Object>>() {
              @Override
              public Observable<Object> apply(Integer t) throws Exception {
                  return null;
              }
          })
          .test()
          .assertFailureAndMessage(NullPointerException.class, "The itemDelay returned a null ObservableSource");
      }
  }
  